This invention relates to a method and apparatus useful for sorting or separating mixtures of pieces of different metals. It is particularly useful in the sortation of mixtures of irregular, varying size and shape, varying composition, pieces of scrap metal such as shredded automobile scrap metal.
Discarded automotive vehicles are typically broken and shredded into scrap metal pieces. These pieces comprise different metals since different parts of an automotive vehicle are made of different metals. For example, the scrap metal pieces may comprise pieces of ferrous metals, aluminum, zinc, copper, brass, lead, stainless steel, as well as non-metallic pieces of plastic, glass and even stones or rocks.
For the most part, scrap handlers can remove the ferrous metal materials from the mixtures of diverse pieces by utilizing magnets. However, after the removal of ferrous metals by ordinary electromagnets, the remaining mixtures of diverse pieces are of very low value since they cannot be reused as raw materials until the different kinds of materials are separated one from another. Different separation systems have been utilized in the past, such as melting the scrap and separating the material through smelting or chemical processes. Alternatively, separation of the materials has been done by hand utilizing low cost manual laborers to simply visually recognize pieces of different materials and to manually separate these materials.
For economically feasible manual separation, mixtures of different materials are shipped to low labor cost areas of the world, as for example, to a low cost labor oriental country. There, individuals visually select different kinds of material pieces, such as valves, handles, connectors, trim, etc., and manually separate these pieces which are known to be made of different metals. Hence, a piece of a part that is made of zinc or a piece of another part that is made of aluminum can be visually recognized and manually separated.
Once the scrap pieces are separated or sorted into similar metal categories, they can be utilized as raw material by re-melting them reusing the metal. At the same time, non-metallic materials, such as plastic pieces, glass fragments, rocks and the like, can be separated for discarding in a land fill or the like. The value of scrap that is separated into separate types of metals, is considerably greater than, and such scrap is more usable than, mixtures of diverse scrap pieces.
The expense of separating or sorting the mixtures of scrap pieces is considerable. In the case of the utilization of low cost labor, the material often must be shipped considerable distances and then, after sorting, the materials must be returned to places where they can be melted and re-used as raw materials. This transportation is relatively costly. In the case of separation by smelting type processes, considerable expense is involved in the equipment and the processing. Thus, there has been a need for a method and an apparatus for less expensively sorting or separating mixtures of scrap metal materials comprising materials that are left after the removal of iron pieces by the usual magnetic devices which attract the magnetically attractable ferrous materials.
The invention of this application focuses on a system for physically separating mixed pieces of non-ferrous metals, which normally are not amenable to magnetic separation, by utilizing magnetic forces, so as to substantially eliminate the need for manual labor.